Schizophrenia

Schizophrenia is a chronic mental disorder characterised by episodes of psychosis, which include hallucinations, delusions, and disorganised thinking and behaviour. This disorder often leads to a misperception of reality, social withdrawal, and flat or inappropriate affect.

The onset typically occurs between the ages of 16 and 30, with symptoms developing gradually and persisting throughout life.

Signs and Symptoms

Positive Symptoms

Positive symptoms are those that add abnormal experiences, including hallucinations, delusions, and disorganised thoughts and behaviour. Hallucinations, experienced by 80% of those with schizophrenia, commonly involve hearing voices but can affect any of the senses. Delusions often manifest as bizarre or persecutory beliefs. These symptoms are generally responsive to medication.

Negative Symptoms

Negative symptoms are deficits of normal emotional responses and thought processes. They include blunted affect, alogia (poverty of speech), anhedonia (inability to feel pleasure), asociality (lack of desire to form relationships), and avolition (lack of motivation). These symptoms are less responsive to medication and more challenging to treat.

Cognitive Symptoms

Cognitive symptoms affect 70% of those with schizophrenia and include deficits in memory, attention, problem-solving, and social cognition. These symptoms are often evident before the onset of the illness and remain relatively stable over time. Cognitive impairments are a significant predictor of functional outcomes.

Diagnosis

Schizophrenia is diagnosed based on criteria in the DSM-5 or ICD-11, which involve self-reported experiences and observed abnormalities in behaviour. The DSM-5 requires two diagnostic criteria over one month, significantly impacting social or occupational functioning for at least six months. One symptom must be delusions, hallucinations, or disorganised speech. Various scales, such as the Positive and Negative Syndrome Scale (PANSS), are used to assess symptom severity.

Causes and Risk Factors

Genetic Factors

Schizophrenia has a high heritability estimate of 70-80%, with the highest risk being in first-degree relatives. Various genetic loci and rare copy number variations (CNVs) are implicated, with some CNVs increasing the risk by up to 20-fold.

Environmental Factors

Several environmental factors contribute to the risk of developing schizophrenia, including prenatal stress, maternal malnutrition, infections, and adverse childhood experiences. Urban upbringing, social isolation, and substance use, particularly cannabis, are also significant risk factors.

Treatment and Management

Medication

The primary treatment is antipsychotic medication, which includes first-generation (typical) and second-generation (atypical) antipsychotics. These medications primarily affect dopamine and serotonin neurotransmission. About half of the patients respond favourably, but a significant portion remains treatment-resistant, requiring the use of clozapine.

Psychosocial Interventions

Psychosocial interventions include cognitive behavioural therapy (CBT), family therapy, and social support services. Assertive community treatment (ACT) and intensive care management (ICM) are used to support severe cases, focusing on long-term care and community integration.

Lifestyle and Dietary Interventions

Exercise has shown benefits in improving symptoms and cognitive functions. Nutritional deficiencies, particularly in folate and vitamin D, are common and supplementation is recommended. An unhealthy diet is often associated with schizophrenia, contributing to comorbid conditions like cardiovascular disease.

Prognosis

Schizophrenia significantly reduces life expectancy by 20-28 years, primarily due to associated health conditions such as heart disease and diabetes. The disorder is a major cause of disability, with a high unemployment rate and social exclusion. The suicide rate is significantly higher than the general population, with a strong association with substance use disorders.

---

Self-assessment MCQs (single best answer)

Which age range typically marks the onset of schizophrenia?

Which of the following is considered a positive symptom of schizophrenia?

What percentage of individuals with schizophrenia experience hallucinations?

Which symptom is characterised by a lack of desire to form relationships?

What is the primary focus of medications used to treat schizophrenia?

Which psychosocial intervention is aimed at long-term care and community integration for severe cases of schizophrenia?

What is the estimated heritability percentage of schizophrenia?

Which of the following is NOT a cognitive symptom of schizophrenia?

Which antipsychotic medication is commonly used for treatment-resistant schizophrenia?

What factor is NOT considered a significant risk factor for developing schizophrenia?